A usual design of a side airbag module includes a gas generator mounted inside a cavity in a side bolster of a back rest of a vehicle seat. The gas generator is mounted on a backside of the seat cavity and projects inflation gas in a forward direction of the vehicle. In the seat cavity, a folded airbag is arranged around and attached to the gas generator. The seat cavity is enclosed by a cover made of a molded shell of optically appealing plastic material that conceals the airbag module. The cover has an intentionally weakened seam or line of reduced thickness designed to break when the gas generator inflates the airbag.
The above-described known airbag arrangement, in which the gas generator is mounted in the side bolster of the vehicle seat back, has the disadvantage that each part of the gas generator must be individually attached to a fastening structure inside the seat cavity that may not be easily accessible for assembly.